Question
I live in the Puget Sound area.  I'm not concerned about the grass, but the dandelions that grow in it.

Can you tell me at what stage the dandelion seeds become viable?  If I cut off the yellow flowers with a weedeater just after they open, will that prevent the heads from reseeding? Or do I have to actively remove the heads?

Answer
Hi Richard Nerf,

This is an interesting question since I too have also observed that herbicide  (2-4-D) treated Dandelion weedy plants will experience the effects of the herbicide  (namely fatal hormone potentiated 'hyper-activity'), BUT  apparently continue to have enough physiologic integrity to produce viable seeds even as the rest of the plant shrivels to an eventual demise.  Removing the flower buds before they open may indeed be the only way to avoid the plant's way to propagate even when 2-4-D has been absorbed into the plant tissues.  I am sure there must be scientific research and studies concerning this and these facts (to determine the halting effects for germintation-biosynthesis of the chemical), but as far as the home-owner is concerned it just means you should zilch the weeds as soon as you see them in the landscape and any delay may only mean that the herbicide effects are less efficient.
__ Jim Gibbs,
  Botanist/Microbiologist.